Lec 6 | MIT 3.091SC Introduction to Solid State Chemistry, Fall 2010
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- Опубліковано 12 вер 2024
- Lecture 6: Particle-Wave Duality
Instructor: Donald Sadoway
View the complete course: ocw.mit.edu/3-0...
License: Creative Commons BY-NC-SA
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i started watching these lectures 6 years ago. My first attempt to freshman level chemistry. I have watched these series of lecture at least 3 times. I am now a graduate of CCSU in chemistry and watching these again as I prepare for my GRE's. The ironic thing is I am looking to get into a grad program on polymer chemistry -> solid state chemistry. Dr. Sadoway thank you for inspiring me!
Well he clearly states that MIT is the only place to study solid state chemistry... we are three years from your comment... hope you made it.
This is crystal clear. Thanks professor.
He loves writing. And his handwriting is good.
The island is on the coast of Germany, it is Heligoland.
Am I right in saying that he is wrong at around 39:50? He is mixing up the observer effect with the Heisenberg uncertainty principle. The uncertainty is inherent in quantum mechanics and in the wave nature of the particles. The effect of interference from measurement using a photon is a separate issue, known as the observer effect.
paused at that exact moment, scratched my head, went down here, found your post. Thumbs up!
neil15oo no neil he is giving a statistical uncertanity ...i am guessing you have not studied quantum mechanics in great detail. he is not even wrong.
No I have only studied quantum mechanics in my spare time. I am aware that he is correct in that there is statistical uncertainty, but his explanation of it is what is incorrect. He was describing the Heisenberg uncertainty principle, which was a newly discovered phenomenon in quantum systems; but his examples were of the observer effect, which is a problem that has been noted for centuries and that occurs in classical and quantum physics.
You are not right to say he is wrong. the double slit experiment is an example of the observer effect...the Heisenberg UP tells us we cannot know both the position or momentum with accuracy, one at the cost of the other, he was also pointing out that experimentally the observation effect comes in to play.... he has not mixed them up at all, you obviously understand what they are, he has just covered all of the angles quickly, like the pimp prof... He also has a class full of hand picked ubernerds.
Thank you!
This guy is fucking awesome
16:00 Why does Hund's rule necessitate the unpaired electrons to have same spins?
Good question. And we know how important a good question is.
I would like to see Professor Sadoway's response. Here is mine
www.chem.purdue.edu/jmol/gloss/hundsrule.html gives
Hund's rule:
Every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied,
And,
All electrons in singly occupied orbitals have the same spin.
(my punctuation and formatting)
Perhaps, we should refer to Hund's Rules [...for the electron filling sequence of atoms in this universe, the one we observe] in the plural.
My sense is the Second Rule, of which you speak, is qualitatively no different to the First, in the sense that both rules are necessary constraints to the math to describe the actual observations. When so constrained "Reality" and "The Model" are aligned: the right number of emission and absorbtion lines, in the right places, are always observed and that the explanation is sufficient - there are no unexplained lines.
What lies behind your question? To me, it feels like you are asking a very interesting question: "What would a universe with different Hund Rules, be like?"
I find myelf asking: Is it possible to build out a Periodic Table of elements, and their properties, using the same elemental nucleii but using different shell filling rules? Do we get anywhere exploring the implications of the different possible filling sequences: a universe with different, but predictable chemistry perhaps?
My understanding is that the fine constant is indeed "finely tuned", any small variation in its value and the universe doesn't get to form stars that produce chemistry. But Hund is pure quantised rule logic - and there is nothing (yet identified? to be identied?) that dictates it must be so. It just is.
It is temping to say that the conclusion from all of this is that despite Eddington's estimate of 10^78 protons in the universe, and, "exactly the same number of electrons", and given 13.8 x 10^9 years of apparent observation, no evidence exists to suggest that any combination of protons and neutrons (Z=1, 2,3...111) has EVER, permitted an electron to fill an orbital other than according to Hund's Rules. Moreover, the prediction is it NEVER will.
Blimey!
Perhaps there is a kind of resonance that establishes spin synchronisation, like pendulum synchronisation.
At 37:30 and beyond how is the value of indeterminacy of velocity and position determined?
He loves writing. And his handwriting is good.